The present invention relates generally to a manner by which to facilitate selection of a power level at which to send data in a radio communication system, such as a cellular communication system constructed pursuant to an IS-95 standard in which 1xc3x97EV-DO technology is deployed. More particularly, the present invention relates to apparatus, and an associated method, by which to select the power levels at which to send data upon a data channel, such as MAC data upon an MAC channel, to a mobile, or other communication, station. The mobile station generates a data rate request to request that the data be sent to the mobile station at a requested data rate. The requested data rate is used, in part, to select the power level at which the data is communicated. And, when the channel is used to communicate separate data to a plurality of separate mobile stations, the power levels at which the data is communicated is allocated in manners such that the total power level to communicate all of the separate data to all of the separate mobile stations is within a maximum allowable level. Power control is effectuated while utilizing an existing communication metric of data rate feedback requests.
Advancements in communication technologies have permitted the introduction, and popularization of new types of communication systems. In various of such new types of communication systems, the rates of data transmission and the corresponding amount of data permitted to be communicated, has increased relative to existing types of communication systems.
New types of radio communication systems are exemplary of communication systems that have been made possible as a result of advancements in communication technologies. Communication channels of a radio communication system are formed upon radio links, thereby obviating the need for conventional wire line connections between sending and receiving stations operable therein. A radio communication system, therefore, inherently permits increased communication mobility in contrast to conventional wire line systems.
A cellular communication system is exemplary of a radio communication system. Cellular communication systems, constructed according to various communication standards, have been installed throughout significant areas of the world. A mobile station operable in the cellular communication system permits a user to communicate telephonically therethrough when the mobile station is positioned within an area encompassed by the communication system.
The development and implementation of new cellular, as well as other, communication systems capable of communicating packet-formatted data have been made possible as a result of advancements in digital communication techniques. An exemplary cellular communication system which provides for the communication of packet-formatted data is set forth in the IS-95 standard promulgated by the EIA/TIA. Ongoing efforts are made to make improvements to the initial implementation of the standard. The IS-2000 standard, for instance, also sets forth operational parameters for a cellular communication system that is predicated, in part, upon the IS-95 system. Both the IS-95 and IS-2000 communication standards utilize CDMA (Code-Division, Multiple-Access) communication techniques. The standards are sometimes referred to as the IS-95/IS-2000 family of standards.
Deployment of a so-called 1xc3x97EV-DO technology together with an IS-95/IS-2000 based communication system has also been proposed. An IS-95 system which deploys 1xc3x97EV-DO technology is an evolutionary step from the IS-2000 system and deploys a packet data wireless technology. The 1xc3x97EV-DO technology is somewhat disjoined from the IS-95/IS-2000 family of standards in that a system in which the 1xc3x97EV-DO technology is deployed is unable to share the same frequencies as the frequencies of existing IS-95 and IS-2000 systems. The 1xc3x97EV-DO technology utilizes TDMA (Time-Division, Multiple-Access) schemes instead of the CDMA access scheme utilized in the IS-95/IS-2000 standards.
In a system in which the 1xc3x97EV-DO technology is deployed, a channel is defined by a frequency and time slot combination. Pursuant to a communication session, system users are assigned time slots upon which to communication to effectuate the communications pursuant to the communication session. The time slots are sub-divided into three basic payloads. A data payload, an MAC (Medium Access Control) payload, and a pilot payload are all defined. And, the payloads each define a channel, i.e., a data channel, a MAC channel, and a pilot channel.
The MAC channel is utilized by all current users, i.e., mobile stations, at least within a selected area. Different users are assigned different Walsh spreading functions. The MAC channel is thereby a shared channel, and the power levels at which data is communicated upon the MAC channel must be controlled.
As presently promulgated, the IS-95 system which deploys 1xc3x97EV-DO technology fails to set forth a power control scheme by which to control the power levels at which data is communicated upon the MAC channel.
A manner by which to control the power levels of data communicated upon a MAC channel would facilitate the communication of the data in a manner to permit its detection at the mobile station to which the data is communicated.
It is in light of this background information related to packet radio communication systems that the significant improvements of the present invention have evolved.
The present invention, accordingly, advantageously provides apparatus, and an associated method, by which to facilitate selection of a power level at which to send the data in a radio communication system, such as a cellular communication system constructed pursuant to an IS-95/IS-2000 standard in which 1xc3x97EV-DO technology is deployed.
Through operation of an embodiment of the present invention, a manner is provided by which to select the power levels at which to send the data upon a data channel, such as MAC (Medium Access Control) data, upon a MAC channel sent upon a forward link to a mobile station.
A mobile station operable to receive the data monitors the received data to determine channel conditions of a radio link upon which the data is communicated. Responsive to measurements made during the monitoring, the mobile station generates a data rate request. The data rate request is a request for the data to be sent thereto at a particular data rate. The requested data rate is used as a metric by which to select the power level at which data is subsequently communicated to the mobile station.
When the channel is used to communicate separate data to a plurality of separate mobile stations, the power levels at which the data is communicated are allocated in manners such that the total power level of all the data communicated upon the data during a selected time interval is within an allowable power level. The total power level is the sum of the power levels of the separate data communicated to the separate mobile stations.
Operation of an embodiment of the present invention thereby advantageously provides a manner by which to effectuate power control over the data transmitted upon the data channel while using a communication metric of data rate feedback.
In one aspect of the present invention, the data channel forms a MAC (Medium Access Control) channel defined in an IS-95/IS-2000 system in which 1xc3x97EV-DO technology is deployed. The MAC channel is formed of a time slot defined in a TDM (Time Division Multiplex) access method. All current users in a portion of the communication system utilize the MAC channel. Each of the users, i.e., mobile stations, are allocated a Walsh function. Data to be communicated to separate ones of the mobile stations are encoded by the separate Walsh functions, thereby providing differentiation upon the MAC channel. Effectuation of power control is facilitated thereby to maintain the power levels at which the data communicated upon the MAC channel are collectively maintained within a maximum allowable level.
In another aspect of the present invention, a mobile station performs measurements to determine channel conditions upon a radio link extending thereto and upon which the MAC channel is defined. Responsive to the measurements, the mobile station determines the maximum data rate at which data subsequently to be sent to the mobile station should be communicated. Generally, when channel conditions are good, data is able to be communicated to the mobile station at relatively high data rates. Conversely, when the communication conditions are poor, the data rate at which data can be sent to the mobile station is relatively low. The mobile station generates a DRC (Data Rate Control) command, or other appropriate indications, of a requested data rate at which to communicate subsequent data to the mobile station.
In another aspect of the present invention, the DRC command, or other indication, is communicated to the network of the IS-95/IS-2000 system in which the 1xc3x97EV-DO technology is deployed. The network detects the DRC command, or other indication, and utilizes the value of the command or indication as a metric by which to select the power levels at which to send subsequent data to the mobile station.
The total amount of power available to communicate separate data to separate mobile stations upon the MAC channel is defined. The total power level is, for instance, a system-defined parameter or, alternately, an operationally-selected parameter value. An average power level available by which to communicate data to N current users, i.e., mobile stations, is determined by dividing the total power level available by the number N of current users. And, the average power allocated to each data communication is further differentiated depending upon the value of the DRC command received at the network. The DRC command is of one of a finite set of values. The value of the DRC command is multiplied together with the average power available to each current user, and the product is multiplied by a gain factor. The gain factor is selected such that the summation of all the power levels at which the separate data are sent to the separate mobile stations upon the MAC channel are within a maximum allowable total power level.
In these and other aspects, therefore, apparatus, and an associated method, is provided for a two-way radio communication system. At least first selected forward-link data is communicated by a network station upon a forward link channel to at least a first selected mobile station. Selection of a power level at which the first selected forward-link data is communicated is facilitated. A first channel quality indicia measurer is positioned at the first selected mobile station. The first channel quality indicia measurer measures an indicia of communication quality levels upon the forward link channel and forms a first channel-quality indicia value responsive thereto. A first data rate selector is coupled to a first channel quality indicia measurer to receive the first channel-quality indicia value. The first data rate selector selects a first data rate at which to communicate subsequent first selected forward-link data upon the forward link and forms a first data rate selection value responsive to selection made thereat. An indication of the first data rate selection value, when returned to the network station, is used to select the power level at which to communicate the subsequent first selected forward-link data to the first selected mobile station.
A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings which are briefly summarized below, the detailed description of the presently preferred embodiments of the invention, and the appended claims.